Image processing apparatus and image processing method

ABSTRACT

An image processing apparatus and method converts a moving image signal into an image data format consisting of a luminance signal and a color-difference signal like that of the YUV format at a signal processing circuit  4 , compression-encodes the image data at a compression circuit  10  and records it on a recording medium  11 , in addition to reducing the same-format image data color-difference signal to generate image data for display, enabling the image processing apparatus for recording a moving image to achieve moving image recording of a quality that is good enough to be used as still images.

FIELD OF THE INVENTION

The present invention relates to an image processing apparatus and imageprocessing method for recording moving image data, and moreparticularly, to an image processing apparatus and image processingmethod capable of recording moving images in consideration of a possibleuse of the recorded moving images as still images.

BACKGROUND OF THE INVENTION

At present, the printing of still images sensed using a digital cameraor the like is common. Moreover, it is also possible to print movingimages sensed with a digital camera and the like, in which case onedesired frame from among the recorded images is extracted and a printmade based on such single frame still image.

However, moving images sensed with a digital camera or the like usuallyhave a resolution of 640 pixels horizontally×480 lines vertically(VGA—Video Graphics Array), which is not a high enough resolution forprinting as a good quality still image. In addition, since the movingimages are assumed to be viewed on a display, the color bandwidth of thevideo signal is limited when recorded. As a result, the color bandwidthof the single-frame still image extracted from the moving image-recordedvideo signals also is reduced by band limitation, so that the quality ofthe picture is poor not only in terms of the resolution (the number ofpixels) but also in terms of the amount of color information. Therefore,moving images are generally unsuitable for purposes of printing. Inorder to print moving images of high picture quality, it is necessary torecord at high resolution with a wideband color signal.

Japanese Patent Application Laid-Open No. 07-322295 proposestransmitting an RGB still image signal in addition to a band-limited YUVmoving image signal along a transmission path for transmittingband-limited moving images, enabling an image output device such as avideo printer to obtain a high quality still image by separating out thestill image signal.

In addition Japanese Patent Application Laid-Open No. 2001-359117proposes inputting an image signal containing color signals and aluminance signal from an image input unit and, if the image signal is amoving image, first, reducing the data amount of the color-differencesignal of the image signal and compressing it together with theluminance signal, and then shifting up and encoding a designated area inthe image so as to improve the picture quality of the designated area.

However, because the video signal transmission apparatus described inJapanese Patent Application Laid-Open No. 07-322295 transmits a stillimage signal composed of component video signals in addition to theband-limited moving image signal, transmission volume increases and thusrequires a wideband memory bus. Therefore, if the bandwidth of thememory bus is narrow, at video signal transmission the band of memorybus may be overloaded, leading in the worst case to a loss oftransmission. When that happens, the image compression ratio increasesand the amount of data of the video signal to be transmitted is reduced,leading to the same deterioration in picture quality that is a problemwith the conventional art.

In addition, with the image processing apparatus described in JapanesePatent Application Laid-Open No. 2001-359117, an image of high picturequality is generated by shifting up and encoding a designated area ofthe image. As a result, however, the remainder of the image is not ofhigh quality and thus the same problem that exists in the conventionalart remains, meaning that the picture quality is not good enough foroutput to a color printer as a still image.

Moreover, since a high quality image is output to a display device atthe same time as a high quality moving image is recorded, the band ofthe memory bus is overloaded at video signal transmission. As a result,the same problem arises as with the video signal transmission apparatusof Japanese Patent Application Laid-Open No. 07-322295

SUMMARY OF THE INVENTION

The present invention is conceived in light of the above-describedcircumstances, and has as its object to provide an image processingapparatus and image processing method capable of recording high qualitymoving images.

According to an aspect of the present invention, there is provided animage processing apparatus for recording a moving image, comprising:signal processing unit adapted to convert an input moving image signalinto first image data composed of a luminance signal and acolor-difference signal and outputting the first image data; encodingunit adapted to encode the first image data frame by frame andoutputting the first image data as compressed image data; recording unitadapted to sequentially record the compressed image data as moving imagedata on a recording medium; and conversion unit adapted to convert thefirst image data into second image data having a reducedcolor-difference signal data amount and outputting the second image dataas image data for display.

According to another aspect of the present invention, there is providedan image processing method for recording a moving image, comprising: asignal processing step of converting an input moving image signal intofirst image data composed of a luminance signal and a color-differencesignal and outputting the first image data; an encoding step ofcompression encoding the first image data frame by frame and outputtingthe first image data as compressed image data; a recording step ofrecording the compressed image data as moving image data in order on arecording medium; and a conversion step of converting the first imagedata into second image data having a reduced color-difference signaldata amount and outputting the second image data as image data fordisplay.

With such a structure, the present invention enables a high qualitymoving image to be recorded, making it possible to obtain a still imageof high picture quality compared to the conventional art even if a givenframe from the moving image is used as a still image.

Other features and advantages of the present invention will be apparentfrom the following description when taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram showing an example of the structure of adigital camera as an image processing apparatus according to a firstembodiment of the present invention;

FIGS. 2A-2C are diagrams illustrating image format conversions in a YUVconversion circuit;

FIG. 3 is a flow chart illustrating a moving image recording process inthe digital camera according to the first embodiment of the presentinvention;

FIG. 4 is a schematic diagram of a state of moving image recording inthe digital camera of the present embodiment;

FIG. 5 is a block diagram showing an example of the structure of adigital camera as an image processing apparatus according to a secondembodiment of the present invention;

FIG. 6 is a flow chart illustrating a moving image recording process inthe digital camera according to the second embodiment of the presentinvention;

FIG. 7 is a block diagram showing a system structure of the imageprocessing apparatus according to a variation of the second embodimentof the present invention;

FIGS. 8A-8C are diagrams showing an image sensing size, a recording sizeand a display size in a digital camera according to the first embodimentof the present invention;

FIGS. 9A-9C are diagrams showing an image sensing size, a recording sizeand a display size in a digital camera according to the secondembodiment of the present invention; and

FIG. 10 is a diagram illustrating the format of the moving image datagenerated by the digital camera according to the embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

First Embodiment

FIG. 1 is a block diagram showing an example of the structure of adigital camera 100 as an image processing apparatus according to a firstembodiment of the present invention.

In FIG. 1, an image sensing lens 1 is, for example, a zoom lens equippedwith an auto focus mechanism. An image sensing device 2 is, for example,a one-chip CCD (Charge Coupled Device). An A/D converter 3 converts ananalog signal output by the image sensing device 2 into a digitalsignal. A signal processing circuit 4 contains a white balanceadjustment circuit, a gamma correction circuit, a YC processing circuit,an exposure/focus (AE/AF) circuit and the like, and outputs data in YUV4:2:2 format video coding. It should be noted that, in the followingdescription, YUV=X:Y:Z format video coding is described simply as YUVXYZformat.

A scaling circuit 5 sub-samples and performs linear compensation on theYUV422 format image data output by the signal processing circuit 4 tochange the size of the image horizontally and/or vertically. A YUVconversion circuit 6 performs color-difference signal interpolation onand sub-sampling of the YUV422 format data for conversion into YUV411format or YUV420 format. A playback circuit 7 adds modulation andsynchronization signals to the image data output by the YUV conversioncircuit 6 and DA converts it to generate a video signal. A display unit8 is, for example, a liquid crystal display monitor, and displays thevideo signal output by the playback circuit 7.

The output of the signal processing circuit 4 is applied to the scalingcircuit 5 and is also supplied to a compression circuit 10. Thecompression circuit 10 carries out block compression encoding of theYUV422 format image data. It is assumed that JPEG (Joint PhotographicExpert Group; a color still image compression method) format encoding iscarried out. The compressed image data is recorded onto a recordingmedium 11 typified by a semiconductor memory by a recording apparatus,not shown.

Overall control of the digital camera is accomplished by a CPU (CentralProcessing Unit) 12 executing a control program stored in a nonvolatilememory, not shown, using a RAM or other memory, not shown.

The digital camera is provided with input devices (switches, levers,touch panels and the like) for enabling the user to input instructionsto the camera, with a release switch 13 and a mode switch 14 comprisingpart of the input devices.

FIGS. 2A-2C are diagrams illustrating image format conversions in a YUVconversion circuit.

FIG. 2A, FIG. 2B and FIG. 2C show the relation between Y (luminance), U(color difference) and V (color difference) in the YUV422, YUV411 andYUV420 formats, respectively.

The YUV422 format is a format that samples the Y at 8 bits per pixel andthe U, V at 8 bits averaged every 2 bits, for a data amount of 16bits/pixel. Both the YUV420 format and the YUV411 format sample the U, Vat 8 bits averaged every four bits, for a data amount of 12 bits/pixel.

FIG. 4 is a schematic diagram of a state of moving image recording inthe digital camera 100 of the present embodiment.

Here, the display unit 8 is made to act as an electronic viewfinder,with an image of the object displayed on the display unit 8 in realtime. When the release switch 13 is fully depressed in this state, stillimage recording or moving image recording starts (or moving imagerecording ends). The mode switch 14 switches the operating modes of thedigital camera 100, and in the present embodiment is capable of settingand switching between a still image sensing mode (REC), a moving imagesensing mode (MOVIE) and a playback mode (PLAY).

Next, a description will be given of the moving image recording processof the digital camera of the present embodiment, using the flow chartshown in FIG. 3.

If the digital camera 100 is set to the moving image recording mode bythe mode switch 14, the CPU 12 carries out the following operations.

In a step S1, the optical system is initialized. In the presentembodiment, the image sensing lens 1 is configured so as to be movablealong the optical axis by a focus drive unit, not shown. The imagesensing device 2 is disposed on the optical axis of the image sensinglens 1. In order to use the display unit 8 as an electronic viewfinder,focus control is then carried out automatically and the sensed image ofthe object shown in FIG. 4 sensed with the image sensing lens 1 isfocused on the image sensing surface of the image sensing device 2.

In a step S2, the image sensing device is driven. In contemporarydigital cameras, the number of pixels of the image sensing device 2exceed the number of pixels that can be displayed on the display unit 8.Therefore, when generating an image for display on the display unit 8,usually a process of reduction is carried out. Here, for the sake ofsimplicity of explanation, it is assumed that the display unit 8 has aresolution of 640 pixels×480 lines and that the resolution of the imagedata output by the image sensing device 2 is the 1024 pixel×768 lines ofXGA (extended Graphics Array).

The object image focused on the image sensing surface of the imagesensing device 2 is photoelectrically converted by the image sensingdevice 2 and output as a succession of analog electrical signals. Then,at the A/D converter 3, these analog signals are converted into digitalsignals. The digitized image signal is then output to the signalprocessing circuit 4.

In a step S3, the image signal digitized by the A/D converter 3 isprocessed by the signal processing circuit 4, which performs whitebalance adjustment, gamma correction, YC processing and the like togenerate image data of the YUV422 format shown in FIG. 2A. An example ofsuch image data is shown in FIG. 8A.

In a step S4, the image data with a resolution of 1024 pixels by 768lines that is output by the signal processing circuit 4 is sub-sampledand linear compensated by the scaling circuit 5, reducing the image datahorizontal and vertically to generate reduced image data (display imagedata) with a resolution of 640 pixels by 480 lines that is the displayunit 8 display size. The reduced image data is shown in FIG. 8C. Thereduced image data is then output to the YUV conversion circuit 6.

In a step S5, the 640×480 reduced image data format generated by thescaling circuit 5 is converted from YUV422 format to YUV411 format bythe YUV conversion circuit 6. This conversion reduces the reduced imagedata color signal data (ultimately, the image data size). The convertedreduced image data is then output to the playback circuit 7.

In a step S6, the YUV411 format display image data input from the YUVconversion circuit 6 is converted to a TV (television) analog signal bythe playback circuit 7 and output to the display unit 8. Specifically,at the playback circuit 7, the display image data is chroma encoded,band corrected and converted into composite signals. By carrying out theprocesses of from step S2 to step S6 in order, the display unit 8functions as an electronic viewfinder like that shown in FIG. 4.

In a step S7, the end of the electronic viewfinder process is determinedbased on detection of the operation of, for example, the mode switch 14,the power switch, or the release switch 13, and ends the process if itshould be ended. By contrast, if the process should not end it proceedsto a step S8.

In step S8, whether or not moving image recording has been instructed isdetermined by whether or not the release switch 13 is ON. In the presentembodiment, moving image recording is deemed ordered if the releaseswitch 13 goes ON when there is no moving image recording, and an end tomoving image recording is deemed ordered if the release switch 13 goesON during moving image recording. The digital camera 100 is deemed to bein a moving image recording standby state when the release switch 13 isOFF in a state in which there is no moving image recording.

In step S8, if it is determined that the digital camera 100 is in astate in which the start of moving image recorded is ordered, theprocess proceeds to a step S10.

In addition, if it is determined that the digital camera 100 is in themoving image recording standby state, the process proceeds to step S2and the moving image recording standby state (electronic viewfinderprocess) continues.

In step S10, the YUV422 format 1024×768 image data shown in FIG. 8B andprocessed by the signal processing circuit 4 is compressed by thecompression circuit 10 using compression encoding such as JPEG format.In other words, the compression circuit 10 converts the raster scanimage data output by the signal processing circuit 4 into block scanimage data, block encodes it, and outputs JPEG data to the recordingmedium 11.

In a step S11, the JPEG data output by the compression circuit 10 isrecorded on the recording medium 11.

Thereafter, steps S1-S11 are repeated until there is a moving imagerecording pause instruction or an end instruction, when JPEG data isrecorded in order on the recording medium 11 while an image continues tobe displayed on the image display unit 18 to obtain the moving imagedata of a format in which still images are arranged in chronologicalorder as shown in FIG. 10.

Thus, as described above, the image processing apparatus according tothe present embodiment provides the moving image signal composed of theluminance signal and the color-difference signals having a higher degreeof resolution than the display image, and further, carries out movingimage recording in which the frames are compression encoded as stillimages. As a result, when extracting and printing out a given frame fromthe moving image, higher picture quality results than conventionally canbe obtained. In other words, the present invention provides recording athigh resolution and a wider color band.

In addition, because the image processing apparatus of the presentinvention records images in a format composed of luminance and colordifferences, it is possible obtain a display image easily from therecording image data. Furthermore, because the display image not onlyhas fewer pixels but also color difference reduction, the displayprocess load is light, enabling power consumption to be reduced.

It should be noted that although in the present embodiment the YUVconversion circuit 6 shown in FIG. 1 outputs YUV411 format image data,alternatively the YUV conversion circuit 6 may be configured so as tooutput image data in YUV420 format. In addition, although the recordingsize is described as XGA, the recording size is not particularly limitedthereto and may be of any size provided that it is greater than theresolution of the display unit 8.

Second Embodiment

Next, a description will be given of a second embodiment of the presentinvention. Whereas in the first embodiment, the image data size outputby the signal processing circuit 4=the recording size>display size, inthe present embodiment the image data size>recording size>the displaysize.

FIG. 5 is a block diagram showing an example of the structure of adigital camera as an image processing apparatus according to the presentembodiment. In the diagram, structures that are the same as those shownin the first embodiment are given the same reference characters. As canbe seen from a comparison with the first embodiment, with the secondembodiment, the only difference is that a second scaling circuit 9 isprovided between the signal processing circuit 4 and the compressioncircuit 10, and therefore a description of those other structures thatare the same as those of the first embodiment of the present inventionis omitted.

The second scaling circuit 9, like the first scaling circuit 5, changesthe size horizontally and vertically of the image data output by thesignal processing circuit 4 using sub-sampling, linear compensation andthe like.

Next, a description is given of a moving image recording process of thedigital camera of the present embodiment. It should be noted that, inFIG. 6 as well, steps that are the same as those of the process shown inFIG. 3 in the description of the first embodiment are given the samereference numerals and a redundant description thereof is omitted here.

The CPU 12 carries out the process shown in FIG. 6 if the digital camerais set to the moving image sensing mode (MOVIE) by the mode switch 14.

The processes of steps S1-S8 are the same as those of the firstembodiment.

In addition, to facilitate explanation and understanding, in the presentembodiment as well, it is assumed that an XGA-size image signal isobtained from the image sensing device 2. In addition, it is assumedthat 1152×864 image data like that shown in FIG. 9A is output from thesignal processing circuit 4 in YUV422 format. Moreover, it is assumedthat the display resolution of the display unit 8 is 640×480 as shown inFIG. 9C. However, unlike in the first embodiment, the recording size isassumed to be the 1024×768 resolution shown in FIG. 9B.

In step S8, when it is determined that the start of moving imagerecording has been ordered, the process proceeds to a step S9.

In step S9, the YUV422 format, 1152×864 image data output by the signalprocessing circuit 4 is changed to the recording size by the secondscaling circuit 9. In other words, the second scaling circuit 9 shrinksthe image data horizontally and vertically by applying sub-sampling,linear compensation and so forth, to the sensed image data. The secondscaling circuit 9 then generates the YUV422 format, 1024×768 reducedimage data (recording image data) shown in FIG. 9B and outputs therecording image data to the compression circuit 10.

In step S10, the recording image data generated by the second scalingcircuit 9 is compression encoded frame by frame by the compressioncircuit 10. In the present embodiment as well, as with the firstembodiment, the compression circuit 10 carries out block compressionencoding (specifically, JPEG encoding). The compression circuit 10converts the raster scan image data into block scan image data, blockencodes it, and outputs JPEG data to the recording medium 11.

In step S11, the JPEG data compressed by the compression circuit 10 isrecorded on the recording medium 11.

Thereafter, steps S1-S11 are repeated and JPEG data is recorded in orderon the recording medium 511 while an image continues to be displayed onthe image display unit 18 to obtain the moving image data shown in FIG.10.

Thus, as described above, the same effect as with the first embodimentcan be obtained with this second embodiment as well. In addition, evenif the recording size is smaller than the image sensing size (the imagesensing size is greater than the recording size), it is still possibleto display on the display unit and to record.

In the present embodiment as well, it should be noted that although theYUV conversion circuit 6 outputs YUV411 format image data, alternativelythe YUV conversion circuit 6 may be configured so as to output imagedata in YUV420 format. In addition, although the recording size is XGA,the recording size is not particularly limited thereto and may be of anysize provided that it is greater than the resolution of the display unit8.

Variation of the Second Embodiment

In the second embodiment, the signal processing circuit 4 image signalshown in FIG. 5 is output to a first scaling circuit 505 and a secondscaling circuit 509. However, alternatively, as shown in FIG. 7, theimage sensing size YUV422 format image data output by the signalprocessing circuit 4 may first be changed to the recording size by thesecond scaling circuit 9. In this case, the output of the second scalingcircuit 9 is output to the first scaling circuit 5 and the compressioncircuit 10 710. Therefore, the first scaling circuit 5 further changesthe recording size image data to the display size.

Other Embodiments

It should be noted that the present invention also includes an instancein which a software program that implements the capabilities of theembodiments described above is supplied by wire or wirelesscommunications to a shading correction apparatus or an image sensingapparatus having a computer capable of executing such program, and thesame capabilities are achieved by the image sensing apparatus executingsuch supplied program.

Accordingly, since the functional processes of the present invention areimplemented by a computer of an apparatus having a shading correctioncapability, the program supplied to and installed in the computer itselfalso accomplishes the present invention. In other words, the computerprogram for implementing the functional processes of the invention isitself also included within the scope of the present invention.

In that case, so long as the system or apparatus has the capabilities ofthe program, the program maybe executed in any form, such as an objectcode, a program executed by an interpreter, or scrip data supplied to anoperating system.

Examples of storage media that can be used for supplying the program aremagnetic storage media such as a floppy disk, a hard disk, or magnetictape, optical/magneto-optical storage media such as an MO, a CD-ROM, aCD-R, a CD-RW, a DVD-ROM, a DVD-R, or a DVD-RW, and a non-volatilesemiconductor memory or the like.

As for the method of supplying the program using wire/wirelesscommunications, there is, for example, a method in which a data file(program data file), either a computer program itself that forms theinvention or a file or the like that is compressed and automaticallyinstalled, and capable of becoming the computer program that comprisesthe invention on a client computer, is stored on a server on a computernetwork, and the program data file is downloaded to a connected clientcomputer. In this case, the program data file may be divided into aplurality of segment files and the segment files distributed amongdifferent servers.

In other words, a server device that downloads program data files thatimplement the functional processes of the present invention by computerto multiple users is also covered by the claims of the presentinvention.

It is also possible to encrypt and store the program of the presentinvention on a storage medium such as a CD-ROM, distribute the storagemedium to users, allow users who meet certain requirements to downloaddecryption key data from a website via the Internet, and allow theseusers to decrypt the encrypted program by using the key data, wherebythe program is installed in the user computer.

Besides the cases where the aforementioned functions according to theembodiments are implemented by executing the read program by computer,an operating system or the like running on the computer may perform allor a part of the actual processing, so that the functions of theforegoing embodiments can be implemented by this processing.

Furthermore, after the program read from the storage medium is writtento a function expansion board inserted into the computer or to a memoryprovided in a function expansion unit connected to the computer, a CPUor the like mounted on the function expansion board or functionexpansion unit performs all or part of the actual processing so that thefunctions of the foregoing embodiment can be implemented by thisprocessing.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the appended claims.

This application claims the benefit of Japanese Patent Application No.2005-159939 filed on May 31, 2005, which is hereby incorporated byreference herein in its entirety.

1. An image processing apparatus for recording a moving image,comprising: a signal processing unit configured to convert an inputmoving image signal into first image data composed of a luminance signaland a color-difference signal and to output said first image data; acompressing unit configured to compress said first image data by apredetermined compressing method and to output the compressed imagedata; a recording unit configured to sequentially record said compressedimage data compressed by said compressing unit as moving image data on arecording medium; and a conversion unit configured to convert said firstimage data into second image data having a reduced ratio of thecolor-difference signal data amount to the luminance signal data amountper predetermined numbers of pixels as compared to that of the firstimage data and as compared to that of the compressed image data, and tooutput said second image data as image data for display; wherein saidcompressing unit does not receive the second image data output from saidconversion unit; wherein said signal processing unit outputs said firstimage data to both said compressing unit and said conversion unit inparallel, wherein a) said compression by said compressing unit forrecording said compressed image data by said recording unit, and b) saidconversion by said conversion unit for displaying said second imagedata, are performed in parallel, and wherein the color-difference signaldata amount of the second image data is less than that of the firstimage data, whereas the luminance signal data amount of the second imagedata is equal to that of the first image data.
 2. The image processingapparatus according to claim 1, wherein said first image data is in aYUV4:2:2 format and said second image data is in a YUV4:1:1 or YUV4:2:0format.
 3. The image processing apparatus according to claim 1, furthercomprising a first scaling unit configured to change said first imagedata into a predetermined display size containing fewer pixels than saidfirst image data, wherein said conversion unit converts said first imagedata after scaling into second image data having a reducedcolor-difference signal data amount.
 4. The image processing apparatusaccording to claim 3, further comprising a second scaling unitconfigured to change said first image data into a size for recordingcontaining fewer pixels than said input moving image signal, whereinsaid compressing unit compresses said first image data of the size forrecording.
 5. The image processing apparatus according to claim 4,wherein said first scaling unit changes the size of said first imagedata of the size for recording to the predetermined display size.
 6. Theimage processing apparatus according to claim 1, wherein said imageprocessing apparatus is a digital camera having a display monitor, andsaid conversion unit outputs the second image data to the displaymonitor.
 7. The image processing apparatus according to claim 6, whereinin the event a user's operation is input during the time when saidsecond image data is output to the display monitor in a movie capturingmode of said digital camera, said compressing unit and said recordingunit start to compress the first image data and record of the compressedimage data, respectively.
 8. An image processing method for recording amoving image, comprising: a signal processing step of converting aninput moving image signal into first image data composed of a luminancesignal and a color-difference signal and outputting the first imagedata; a compressing step of compressing the first image data by acompressing method and outputting the compressed image data; a recordingstep of recording the compressed image data compressed by saidcompressing step as moving image data on a recording medium; and aconversion step of converting the first image data into second imagedata having a reduced ratio of the color-difference signal data amountto the luminance signal data amount per predetermined numbers of pixelscompared to that of the first image data and as compared to that of thecompressed image data, and outputting the second image data as imagedata for display, wherein said compressing step does not receive thesecond image data output from said conversion step; wherein a) saidcompression by said compressing step for recording said compressed imagedata by said recording step, and b) said conversion by said conversionstep for displaying said second image data, are performed on the samefirst image data in parallel, and wherein the color-difference signaldata amount of the second image data is less than that of the firstimage data, whereas the luminance signal data amount of the second imagedata is equal to that of the first image data.
 9. The image processingmethod according to claim 8, wherein the first image data is in aYUV4:2:2 format and the second image data is in a YUV4:1:1 or YUV4:2:0format.
 10. The image processing method according to claim 8, furthercomprising a first scaling step of changing the first image data to apredetermined display size containing fewer pixels than the first imagedata, wherein said conversion step converts the first image data afterscaling into second image data having a reduced color-difference signaldata amount.
 11. The image processing method according to claim 10,further comprising a second scaling step of changing the first imagedata into a size for recording containing fewer pixels than the inputmoving image signal, wherein said compressing step compresses the firstimage data of the size for recording.
 12. The image processing methodaccording to claim 11, wherein said first scaling step changes a size ofthe first image data of the size for recording to the predetermineddisplay size.
 13. The image processing method according to claim 8,wherein said image processing method is performed in a digital camerahaving a display monitor and said conversion step outputs the secondimage data to the display monitor.
 14. The image processing methodaccording to claim 13, wherein in the event a user's operation is inputduring the time that the second image data is output to the displaymonitor in a movie capturing mode of the digital camera, saidcompressing step and said recording step start to compress the firstimage data and record the compressed image data, respectively.